A diagnostic and observation expert system for large TCP/IP‐based internetworks

With the expanding use of the computer networks based on LAN, there is a rapid increase of fault generation. A tremendous amount of time and effort is required in the dissolution of those faults since the origins of those faults are physically distant and the data are difficult to obtain due to the distributed management. In addition, the prevention, as well as the early detection and remedy of faults, are required since a failure may affect a broad range. The authors have constructed a diagnosis/observation expert system LODES for LAN, by constructing a knowledgebase of the experiences in dissolving the failure. LODES discovers the violation of protocol by referring to the TCP/IP‐related protocols, automatic detection of fault (or its indication) by observing packets, and points out the abnormality/missetting of network‐related information of the host. In the diagnosis, it has the feature that the distributed cooperative problem‐solving is executed by communicating among LODES (large internetwork observation and diagnosis expert system) attached to each of the network segments. LODES is actually operated, and it is shown that the phenomena and failures which have not been detected can now be detected.